'Seven Spirits of God' in the Bible

"To the angel of the church in Sardis write: " 'He who holds the seven spirits of God and the seven stars speaks thus: I know what you are doing; you are supposed to be alive, but you are dead.

Out from the throne came flashes of lightning, rumblings, and peals of thunder. In front of the throne seven blazing lamps were burning; they are the seven spirits of God.

Then I saw standing in the center of the throne and of the four animals and of the elders a Lamb which seemed to have been slaughtered. He had seven horns and seven eyes; these are the seven spirits of God, which are sent on errands to all parts of the earth.